KR102040627B1 - Method for receiving sync signal and apparatus therefor - Google Patents

Abstract

The present invention discloses a method in which a terminal receives a synchronization signal in a wireless communication system. In particular, the method includes at least one transmission synchronization signal block among a plurality of synchronization signal block groups grouping a predetermined number of candidate synchronization signal block positions of a synchronization signal block composed of a primary synchronization signal, an auxiliary synchronization signal, and a physical broadcast channel signal. Receive a message including a sync signal block group indicator indicating at least one sync signal block group including a, and based on the message, the at least one transmission sync signal block may be received.

Description

Method for receiving sync signal and apparatus therefor

The present invention relates to a method for receiving a synchronization signal, and an apparatus therefor, and more particularly, to indicate an index of a synchronization signal actually transmitted among synchronization signal candidates determined according to subcarrier intervals, and based on the synchronization signal. And a device therefor.

As time goes by, more communication devices require more communication traffic, and a next generation 5G system, which is an improved wireless broadband communication than the existing LTE system, is required. Called NewRAT, these next-generation 5G systems are divided into communication scenarios such as Enhanced Mobile BroadBand (eMBB) / Ultra-reliability and low-latency communication (URLLC) / Massive Machine-Type Communications (mMTC).

Here, eMBB is a next generation mobile communication scenario having characteristics such as High Spectrum Efficiency, High User Experienced Data Rate, High Peak Data Rate, and URLLC is a next generation mobile communication scenario having characteristics such as Ultra Reliable, Ultra Low Latency, Ultra High Availability, etc. (Eg, V2X, Emergency Service, Remote Control), mMTC is a next generation mobile communication scenario with low cost, low energy, short packet, and mass connectivity. (e.g., IoT).

The present invention provides a method for receiving a synchronization signal and an apparatus therefor.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In a wireless communication system according to an embodiment of the present invention, in a method of receiving a synchronization signal by a terminal, a predetermined number of candidate synchronization signal block positions of a synchronization signal block including a primary synchronization signal, an auxiliary synchronization signal, and a physical broadcast channel signal Receiving a message including a sync signal block group indicator indicating at least one sync signal block group including at least one transmission sync signal block among the plurality of sync signal block groups grouped by; and based on the message, Receiving at least one transmission synchronization signal block.

In particular, the apparatus may further include a first sync signal block indicator indicating the at least one transmit sync signal block included in the at least one sync signal block group.

In addition, the message may be received when the terminal operates in a frequency band exceeding a specific value.

Further, when the terminal operates in a frequency band less than or equal to a specific value, a position where the transmission sync signal block is transmitted in the frequency band less than or equal to the specific value by using a bitmap corresponding to each candidate sync signal block position A second sync signal block indicator indicating a may be received, and a sync signal block may be received based on the second sync signal block indicator.

In addition, the sync signal block group indicator may indicate the one or more sync signal block groups using a bitmap.

The first synchronization signal convex indicator may be information regarding the number of the at least one transmission synchronization signal block included in the one or more synchronization signal block groups.

In addition, the first synchronization signal convex indicator may indicate a position of the at least one transmission synchronization signal block in the one or more synchronization signal block group.

The receiving of the at least one transmission synchronization signal block may not receive a signal other than the at least one transmission synchronization signal block in a resource corresponding to the at least one transmission synchronization signal block.

The second synchronization signal block indicator may further receive a second synchronization signal block indicator indicating a position at which the at least one transmission synchronization signal block is transmitted using a bitmap corresponding to each candidate synchronization signal block position. When there is a conflict between the information of the signal block group indicator and the second synchronization signal block indicator, the at least one transmission synchronization signal block may be received based on the second synchronization signal block indicator.

Further, a product of the number of sync signal block groups that can be indicated by the first sync signal block group indicator and the number of transmit sync signal blocks that can be indicated by the first sync signal block indicator is the second sync signal. It may correspond to the number of transmission synchronization signal blocks that can be indicated by the block indicator.

In a wireless communication system according to the present invention, a terminal for receiving a synchronization signal includes: an RF module for transmitting and receiving a wireless signal with a base station; And a plurality of synchronization signal block groups connected to the RF module and grouping a predetermined number of candidate synchronization signal block positions of a synchronization signal block including a primary synchronization signal, an auxiliary synchronization signal, and a physical broadcast channel signal. And a processor configured to receive a message including a sync signal block group indicator indicating at least one sync signal block group including a signal block, and to receive the at least one transmit sync signal block based on the message. .

In particular, the message may further include a first sync signal block indicator indicating the at least one transmission sync signal block included in the one or more sync signal block groups.

In addition, the message may be received when the terminal operates in a frequency band exceeding a specific value.

In addition, when the terminal operates in a frequency band less than or equal to a specific value, the processor may transmit a transmission sync signal block in a frequency band less than or equal to the specific value by using a bitmap in which each bit corresponds to one candidate sync signal block position. The second synchronization signal block indicator indicating the transmitted position may be received, and the synchronization signal block may be received based on the second synchronization signal block indicator.

In addition, the sync signal block group indicator may indicate the one or more sync signal block groups using a bitmap.

In a wireless communication system according to an embodiment of the present invention, in a method of performing a frequency measurement by a terminal, among candidate sync signal block positions of a sync signal block composed of a main sync signal, an auxiliary sync signal, and a physical broadcast channel signal, Receiving a synchronization signal block indicator indicating at least one candidate synchronization signal block including a transmission synchronization signal block and using the transmission synchronization signal block corresponding to the at least one candidate synchronization signal block, the transmission synchronization signal block The measurement associated with this transmitted frequency can be performed.

In this case, the sync signal block indicator may indicate the at least one candidate sync signal block using a bitmap.

In a wireless communication system, a terminal for measuring a frequency, the terminal comprising: an RF module for transmitting and receiving a radio signal with a base station; And at least one candidate sync signal block including a transmit sync signal block among candidate sync signal block positions of a sync signal block composed of a main sync signal, an auxiliary sync signal, and a physical broadcast channel signal, connected to the RF module. And a processor configured to receive a synchronization signal block indicator and to perform a measurement associated with a frequency at which the transmission synchronization signal block is transmitted using the transmission synchronization signal block corresponding to the at least one candidate synchronization signal block. .

In this case, the sync signal block indicator may indicate the at least one candidate sync signal block using a bitmap.

According to the present invention, even if the number of synchronization signal candidates is greater than or equal to a certain number, the index of the synchronization signal transmitted with a small number of bits can be indicated, thereby reducing the signal overhead.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

FIG. 1 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal and an E-UTRAN based on a 3GPP radio access network standard.
2 is a diagram for explaining a physical channel used in the 3GPP system and a general signal transmission method using the same.
3 is a diagram illustrating a structure of a radio frame used in an LTE system.
4 illustrates a radio frame structure for transmission of a synchronization signal (SS) used in an LTE system.
5 is a diagram illustrating a structure of a downlink radio frame used in the LTE system.
6 is a diagram illustrating a structure of an uplink subframe used in an LTE system.
7 shows examples of a connection scheme of a TXRU and an antenna element.
8 is an example of a self-contained subframe structure.
9 is a diagram for describing an embodiment of mapping a synchronization signal sequence to a resource element.
10 is a diagram for describing an embodiment of generating a main synchronization signal sequence.
11 to 13 are diagrams for describing a result of measuring detection performance and peak to average power ratio (PAPR) performance when a synchronization signal is transmitted according to an embodiment of the present invention.
14 to 15 are diagrams for describing embodiments in which PSS / SSS / PBCH is multiplexed in a synchronization signal.
16 to 22 are diagrams for explaining a method of configuring a synchronization signal burst and a synchronization signal burst set.
23 to 25 are diagrams illustrating a method of indexing a synchronization signal and a method of indicating the index.
26 to 42 are diagrams for a result of measuring performance according to an embodiment of the present invention.
43 to 44 are diagrams for describing embodiments of setting bandwidths for a synchronization signal and a downlink common channel.
45 is a block diagram illustrating a communication device according to one embodiment of the present invention.

The construction, operation, and other features of the present invention will be readily understood by the embodiments of the present invention described with reference to the accompanying drawings. The embodiments described below are examples in which technical features of the present invention are applied to a 3GPP system.

Although the present specification describes an embodiment of the present invention using an LTE system and an LTE-A system, this as an example may be applied to any communication system corresponding to the above definition.

In addition, the specification of the base station may be used as a generic term including a remote radio head (RRH), an eNB, a transmission point (TP), a reception point (RP), a relay, and the like.

FIG. 1 is a diagram illustrating a control plane and a user plane structure of a radio interface protocol between a terminal and an E-UTRAN based on a 3GPP radio access network standard. The control plane refers to a path through which control messages used by a user equipment (UE) and a network to manage a call are transmitted. The user plane refers to a path through which data generated at an application layer, for example, voice data or Internet packet data, is transmitted.

The physical layer, which is the first layer, provides an information transfer service to an upper layer by using a physical channel. The physical layer is connected to the upper layer of the medium access control layer through a transport channel. Data moves between the medium access control layer and the physical layer through the transmission channel. Data moves between the physical layer between the transmitting side and the receiving side through the physical channel. The physical channel utilizes time and frequency as radio resources. In detail, the physical channel is modulated in an Orthogonal Frequency Division Multiple Access (OFDMA) scheme in downlink, and modulated in a Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme in uplink.

The medium access control (MAC) layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. The function of the RLC layer may be implemented as a functional block inside the MAC. The Packet Data Convergence Protocol (PDCP) layer of the second layer performs a header compression function to reduce unnecessary control information in order to efficiently transmit IP packets such as IPv4 or IPv6 in a narrow bandwidth wireless interface.

The Radio Resource Control (RRC) layer located at the bottom of the third layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transmission channels, and physical channels in connection with configuration, reconfiguration, and release of radio bearers. The radio bearer refers to a service provided by the second layer for data transmission between the terminal and the network. To this end, the RRC layers of the UE and the network exchange RRC messages with each other. If there is an RRC connected (RRC Connected) between the UE and the RRC layer of the network, the UE is in an RRC connected mode, otherwise it is in an RRC idle mode. The non-access stratum (NAS) layer above the RRC layer performs functions such as session management and mobility management.

The downlink transmission channel for transmitting data from the network to the UE includes a broadcast channel (BCH) for transmitting system information, a paging channel (PCH) for transmitting a paging message, and a downlink shared channel (SCH) for transmitting user traffic or a control message. have. Traffic or control messages of a downlink multicast or broadcast service may be transmitted through a downlink SCH or may be transmitted through a separate downlink multicast channel (MCH). The uplink transmission channel for transmitting data from the terminal to the network includes a random access channel (RAC) for transmitting an initial control message and an uplink shared channel (SCH) for transmitting user traffic or a control message. Above the transmission channel, the logical channel mapped to the transmission channel includes a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and an MTCH (multicast). Traffic Channel).

FIG. 2 is a diagram for explaining physical channels used in a 3GPP system and a general signal transmission method using the same.

If the UE is powered on or enters a new cell, the UE performs an initial cell search operation such as synchronizing with the base station (S201). To this end, the terminal may receive a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station to synchronize with the base station and obtain information such as a cell ID. have. Thereafter, the terminal may receive a physical broadcast channel from the base station to obtain broadcast information in a cell. Meanwhile, the terminal may receive a downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE acquires more specific system information by receiving a physical downlink control channel (PDSCH) according to a physical downlink control channel (PDCCH) and information on the PDCCH. It may be (S202).

On the other hand, when the first access to the base station or there is no radio resource for signal transmission, the terminal may perform a random access procedure (RACH) for the base station (steps S203 to S206). To this end, the UE may transmit a specific sequence as a preamble through a physical random access channel (PRACH) (S203 and S205), and receive a response message for the preamble through the PDCCH and the corresponding PDSCH ( S204 and S206). In the case of contention-based RACH, a contention resolution procedure may be additionally performed.

After performing the above-described procedure, the UE performs a PDCCH / PDSCH reception (S207) and a physical uplink shared channel (PUSCH) / physical uplink control channel (Physical Uplink) as a general uplink / downlink signal transmission procedure. Control Channel (PUCCH) transmission (S208) may be performed. In particular, the terminal receives downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the terminal, and the format is different according to the purpose of use.

Meanwhile, the control information transmitted by the terminal to the base station through the uplink or received by the terminal from the base station includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), and a rank indicator (RI). ), And the like. In the 3GPP LTE system, the terminal may transmit the above-described control information such as CQI / PMI / RI through the PUSCH and / or PUCCH.

3 is a diagram illustrating a structure of a radio frame used in an LTE system.

Referring to FIG. 3, a radio frame has a length of 10 ms (327200 Х T _s ) and consists of 10 equally sized subframes. Each subframe is 1ms long and consists of two slots. Each slot has a length of 0.5ms (15360ХT _s ). Here, T _s represents a sampling time and is represented by Ts = 1 / (15 kHz Х 2048) = 3.2552 Х 10 ^-8 (about 33 ns). The slot includes a plurality of OFDM symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. In the LTE system, one resource block includes 12 subcarriers Х 7 (6) OFDM symbols. Transmission Time Interval (TTI), which is a unit time at which data is transmitted, may be determined in units of one or more subframes. The structure of the radio frame described above is merely an example, and the number of subframes included in the radio frame, the number of slots included in the subframe, and the number of OFDM symbols included in the slot may be variously changed.

4 illustrates a radio frame structure for transmission of a synchronization signal (SS) in an LTE / LTE-A based wireless communication system. In particular, FIG. 3 illustrates a radio frame structure for transmission of a synchronization signal and a PBCH in a frequency division duplex (FDD), and FIG. 5 (a) is configured as a normal cyclic prefix (CP). 5 shows a transmission position of the SS and PBCH in a radio frame, and FIG. 5 (b) shows a transmission position of the SS and PBCH in a radio frame set as an extended CP.

Referring to FIG. 4, the SS will be described in more detail as follows. SS is classified into a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). PSS is used to obtain time domain synchronization and / or frequency domain synchronization such as OFDM symbol synchronization, slot synchronization, etc., and SSS is used for frame synchronization, cell group ID and / or cell CP configuration (i.e., general CP or extension). It is used to get usage information of CP). 4, PSS and SSS are transmitted in two OFDM symbols of each radio frame, respectively. Specifically, in order to facilitate inter-RAT measurement, the SS may be configured in the first slot of subframe 0 and the first slot of subframe 5 in consideration of 4.6 ms, which is a Global System for Mobile Communication (GSM) frame length. Each is transmitted. In particular, the PSS is transmitted in the last OFDM symbol of the first slot of subframe 0 and the last OFDM symbol of the first slot of subframe 5, respectively, and the SSS is the second to second OFDM symbols and subframe of the first slot of subframe 0, respectively. Are transmitted in the second to second OFDM symbols, respectively, at the end of the first slot of five. The boundary of the radio frame can be detected through the SSS. The PSS is transmitted in the last OFDM symbol of the slot and the SSS is transmitted in the OFDM symbol immediately before the PSS. The transmission diversity scheme of the SS uses only a single antenna port and is not defined in the standard.

Since the PSS is transmitted every 5 ms, the UE detects the PSS to know that the corresponding subframe is one of the subframe 0 and the subframe 5, but the subframe may not know what the subframe 0 and the subframe 5 specifically. . Therefore, the UE does not recognize the boundary of the radio frame only by the PSS. That is, frame synchronization cannot be obtained only by PSS. The UE detects the boundary of the radio frame by detecting the SSS transmitted twice in one radio frame but transmitted as different sequences.

The UE that performs a cell discovery process using PSS / SSS and determines a time and frequency parameter required to perform demodulation of DL signals and transmission of UL signals at an accurate time point is further determined from the eNB. In order to communicate with the eNB, system information required for system configuration of the system must be obtained.

System information is configured by a Master Information Block (MIB) and System Information Blocks (SIBs). Each system information block includes a collection of functionally related parameters, and includes a master information block (MIB), a system information block type 1 (SIB1), and a system information block type according to the included parameters. 2 (System Information Block Type 2, SIB2), SIB3 ~ SIB17 can be classified.

The MIB contains the most frequently transmitted parameters that are necessary for the UE to have initial access to the eNB's network. The UE may receive the MIB via a broadcast channel (eg, PBCH). The MIB includes a downlink system bandwidth (dl-Bandwidth, DL BW), a PHICH configuration, and a system frame number (SFN). Therefore, the UE can know the information on the DL BW, SFN, PHICH configuration explicitly by receiving the PBCH. On the other hand, the information that the UE implicitly (implicit) through the reception of the PBCH includes the number of transmit antenna ports of the eNB. Information about the number of transmit antennas of the eNB is implicitly signaled by masking (eg, XOR operation) a sequence corresponding to the number of transmit antennas to a 16-bit cyclic redundancy check (CRC) used for error detection of the PBCH.

SIB1 includes not only information on time domain scheduling of other SIBs, but also parameters necessary for determining whether a specific cell is a cell suitable for cell selection. SIB1 is received by the UE through broadcast signaling or dedicated signaling.

The DL carrier frequency and the corresponding system bandwidth can be obtained by the MIB carried by the PBCH. The UL carrier frequency and corresponding system bandwidth can be obtained through system information that is a DL signal. When receiving the MIB, if there is no valid system information stored for the cell, the UE applies the value of the DL BW in the MIB to the UL-bandwidth (UL BW) until a system information block type 2 (SystemInformationBlockType2, SIB2) is received. . For example, the UE may acquire a system information block type 2 (SystemInformationBlockType2, SIB2) to determine the entire UL system band that can be used for UL transmission through UL-carrier frequency and UL-bandwidth information in the SIB2. .

In the frequency domain, PSS / SSS and PBCH are transmitted only within a total of six RBs, that is, a total of 72 subcarriers, three on the left and right around a DC subcarrier within a corresponding OFDM symbol, regardless of the actual system bandwidth. Therefore, the UE is configured to detect or decode the SS and the PBCH regardless of the downlink transmission bandwidth configured for the UE.

After the initial cell discovery, the UE may perform a random access procedure to complete the access to the eNB. To this end, the UE may transmit a preamble through a physical random access channel (PRACH) and receive a response message for the preamble through a PDCCH and a PDSCH. In case of contention based random access, additional PRACH transmission and contention resolution procedure such as PDCCH and PDSCH corresponding to the PDCCH may be performed.

After performing the above-described procedure, the UE may perform PDCCH / PDSCH reception and PUSCH / PUCCH transmission as a general uplink / downlink signal transmission procedure.

The random access process is also referred to as a random access channel (RACH) process. The random access procedure is used for various purposes, such as initial access, random access procedure, initial access, uplink synchronization coordination, resource allocation, handover, and the like. The random access process is classified into a contention-based process and a dedicated (ie non-competition-based) process. The contention-based random access procedure is generally used, including initial access, and the dedicated random access procedure is limited to handover and the like. In the contention-based random access procedure, the UE randomly selects a RACH preamble sequence. Therefore, it is possible for a plurality of UEs to transmit the same RACH preamble sequence at the same time, which requires a contention cancellation process later. On the other hand, in the dedicated random access process, the UE uses the RACH preamble sequence that is allocated only to the UE by the eNB. Therefore, the random access procedure can be performed without collision with another UE.

The contention-based random access procedure includes four steps. Hereinafter, the messages transmitted in steps 1 to 4 may be referred to as messages 1 to 4 (Msg1 to Msg4), respectively.

Step 1: RACH preamble (via PRACH) (UE to eNB)

Step 2: random access response (RAR) (via PDCCH and PDSCH) (eNB to UE)

Step 3: Layer 2 / Layer 3 message (via PUSCH) (UE to eNB)

Step 4: Contention Resolution Message (eNB to UE)

The dedicated random access procedure includes three steps. Hereinafter, the messages transmitted in steps 0 to 2 may be referred to as messages 0 to 2 (Msg0 to Msg2), respectively. As part of the random access procedure, uplink transmission (ie, step 3) corresponding to the RAR may also be performed. The dedicated random access procedure may be triggered using a PDCCH (hereinafter, referred to as a PDCCH order) for the purpose of instructing the base station to transmit the RACH preamble.

Step 0: RACH preamble allocation via dedicated signaling (eNB to UE)

Step 1: RACH preamble (via PRACH) (UE to eNB)

Step 2: Random Access Response (RAR) (via PDCCH and PDSCH) (eNB to UE)

After transmitting the RACH preamble, the UE attempts to receive a random access response (RAR) within a pre-set time window. Specifically, the UE attempts to detect a PDCCH (hereinafter, RA-RNTI PDCCH) having a random access RNTI (RA-RNTI) (eg, CRC in the PDCCH is masked to RA-RNTI) within a time window. Upon detecting the RA-RNTI PDCCH, the UE checks whether there is a RAR for itself in the PDSCH corresponding to the RA-RNTI PDCCH. The RAR includes timing advance (TA) information indicating timing offset information for UL synchronization, UL resource allocation information (UL grant information), a temporary terminal identifier (eg, temporary cell-RNTI, TC-RNTI), and the like. . The UE may perform UL transmission (eg, Msg3) according to the resource allocation information and the TA value in the RAR. HARQ is applied to UL transmission corresponding to the RAR. Therefore, after transmitting the Msg3, the UE may receive reception response information (eg, PHICH) corresponding to the Msg3.

The random access preamble, ie, the RACH preamble, consists of a cyclic prefix of length T _CP and a sequence portion of length T _{SEQ in} the physical layer. The T _SEQ of the T _CP depends on the frame structure and the random access configuration. The preamble format is controlled by higher layers. The PACH preamble is transmitted in a UL subframe. Transmission of the random access preamble is restricted to certain time and frequency resources. These resources are referred to as PRACH resources, and the PRACH resources are numbered in order of subframe number in the radio frame, followed by increasing PRBs in the frequency domain, so that index 0 corresponds to the lower number PRB and subframe in the radio frame. Lose. Random access resources are defined according to the PRACH configuration index (see 3GPP TS 36.211 standard document). The PRACH configuration index is given by the higher layer signal (sent by the eNB).

In the LTE / LTE-A system, the subcarrier spacing for the random access preamble, that is, the RACH preamble, is defined as 1.25 kHz for the preamble formats 0 to 3 and 7.5 kHz for the preamble format 4 (3GPP TS 36.211 Reference).

FIG. 5 is a diagram illustrating a control channel included in a control region of one subframe in a downlink radio frame.

Referring to FIG. 5, a subframe consists of 14 OFDM symbols. According to the subframe configuration, the first 1 to 3 OFDM symbols are used as the control region and the remaining 13 to 11 OFDM symbols are used as the data region. In the drawings, R1 to R4 represent reference signals (RSs) or pilot signals for antennas 0 to 3. The RS is fixed in a constant pattern in a subframe regardless of the control region and the data region. The control channel is allocated to a resource to which no RS is allocated in the control region, and the traffic channel is also allocated to a resource to which no RS is allocated in the data region. Control channels allocated to the control region include PCFICH (Physical Control Format Indicator CHannel), PHICH (Physical Hybrid-ARQ Indicator CHannel), PDCCH (Physical Downlink Control CHannel).

The PCFICH is a physical control format indicator channel and informs the UE of the number of OFDM symbols used for the PDCCH in every subframe. The PCFICH is located in the first OFDM symbol and is set in preference to the PHICH and PDCCH. The PCFICH is composed of four Resource Element Groups (REGs), and each REG is distributed in a control region based on a Cell ID (Cell IDentity). One REG is composed of four resource elements (REs). The RE represents a minimum physical resource defined by one subcarrier and one OFDM symbol. The PCFICH value indicates a value of 1 to 3 or 2 to 4 depending on the bandwidth and is modulated by Quadrature Phase Shift Keying (QPSK).

The PHICH is a physical hybrid automatic repeat and request (HARQ) indicator channel and is used to carry HARQ ACK / NACK for uplink transmission. That is, the PHICH indicates a channel through which DL ACK / NACK information for UL HARQ is transmitted. The PHICH consists of one REG and is scrambled cell-specifically. ACK / NACK is indicated by 1 bit and modulated by binary phase shift keying (BPSK). The modulated ACK / NACK is spread with Spreading Factor (SF) = 2 or 4. A plurality of PHICHs mapped to the same resource constitutes a PHICH group. The number of PHICHs multiplexed into the PHICH group is determined according to the number of spreading codes. The PHICH (group) is repeated three times to obtain diversity gain in the frequency domain and / or the time domain.

The PDCCH is a physical downlink control channel and is allocated to the first n OFDM symbols of a subframe. Here, n is indicated by the PCFICH as an integer of 1 or more. The PDCCH consists of one or more CCEs. The PDCCH informs each UE or UE group of information related to resource allocation of a paging channel (PCH) and a downlink-shared channel (DL-SCH), an uplink scheduling grant, and HARQ information. Paging channel (PCH) and downlink-shared channel (DL-SCH) are transmitted on the PDSCH. Accordingly, the base station and the terminal generally transmit and receive data through the PDSCH except for specific control information or specific service data.

Data of the PDSCH is transmitted to which UE (one or a plurality of UEs), and information on how the UEs should receive and decode PDSCH data is included in the PDCCH and transmitted. For example, a specific PDCCH is CRC masked with a Radio Network Temporary Identity (RNTI) of "A", a radio resource (eg, frequency location) of "B" and a DCI format of "C", that is, a transmission format. Assume that information about data transmitted using information (eg, transmission block size, modulation scheme, coding information, etc.) is transmitted through a specific subframe. In this case, the terminal in the cell monitors, that is, blindly decodes, the PDCCH in the search region by using the RNTI information of the cell, and if there is at least one terminal having an "A" RNTI, the terminals receive and receive the PDCCH. The PDSCH indicated by "B" and "C" is received through the information of one PDCCH.

6 is a diagram illustrating a structure of an uplink subframe used in an LTE system.

Referring to FIG. 6, an uplink subframe may be divided into a region to which a Physical Uplink Control CHannel (PUCCH) carrying control information is allocated and a region to which a Physical Uplink Shared CHannel (PUSCH) carrying user data is allocated. The middle part of the subframe is allocated to the PUSCH, and both parts of the data area are allocated to the PUCCH in the frequency domain. The control information transmitted on the PUCCH includes ACK / NACK used for HARQ, Channel Quality Indicator (CQI) indicating a downlink channel state, RI (Rank Indicator) for MIMO, and scheduling request (SR), which is an uplink resource allocation request. There is this. The PUCCH for one UE uses one resource block occupying a different frequency in each slot in a subframe. That is, two resource blocks allocated to the PUCCH are frequency hoped at the slot boundary. In particular, FIG. 6 illustrates that PUCCH having m = 0, PUCCH having m = 1, PUCCH having m = 2, and PUCCH having m = 3 are allocated to a subframe.

Hereinafter, channel state information (CSI) reporting will be described. In the current LTE standard, there are two transmission schemes, an open-loop MIMO operated without channel state information and a closed-loop MIMO operated based on channel state information. In particular, in a closed loop MIMO, each of the base station and the terminal may perform beamforming based on channel state information in order to obtain a multiplexing gain (multiplexing gain) of the MIMO antenna. The base station instructs the terminal to feed back the channel state information (CSI) for the downlink signal by assigning a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) to the terminal.

CSI is largely classified into three types of information such as rank indicator (RI), precoding matrix index (PMI), and channel quality indication (CQI). First, as described above, RI represents rank information of a channel, and means the number of streams that a UE can receive through the same frequency-time resource. In addition, since the RI is determined by the long term fading of the channel, the RI is fed back to the base station at a longer period than the PMI and CQI values.

Secondly, PMI is a value reflecting spatial characteristics of a channel and represents a precoding matrix index of a base station preferred by a terminal based on a metric such as SINR. Finally, CQI is a value representing the strength of the channel, which means the reception SINR that can be obtained when the base station uses PMI.

In the 3GPP LTE-A system, the base station may configure a plurality of CSI processes to the UE, and receive and report the CSI for each CSI process. Here, the CSI process is composed of a CSI-RS resource for signal quality specification from a base station and an interference measurement (CSI-IM) resource for interference measurement, that is, an IMR (interference measurement resource).

In millimeter wave (mmW), the wavelength is shortened, allowing the installation of multiple antenna elements in the same area. Specifically, in the 30 GHz band, the wavelength is 1 cm, and a total of 64 (8x8) antenna elements in a 2D (dimension) array form at 0.5 lambda intervals can be installed in a panel of 4 by 4 cm. Therefore, recent trends in the mmW field have attempted to increase the coverage or increase the throughput by increasing the beamforming gain using a plurality of antenna elements.

In this case, if a TXRU (Transceiver Unit) is provided to enable transmission power and phase adjustment for each antenna element, independent beamforming is possible for each frequency resource. However, in order to install TXRU in all 100 antenna elements, there is a problem in terms of cost effectiveness. Therefore, a method of mapping a plurality of antenna elements to one TXRU and adjusting the direction of the beam by an analog phase shifter is considered. The analog beamforming method has a disadvantage in that only one beam direction can be made in the entire band and thus frequency selective beamforming cannot be performed.

A hybrid BF having B TXRUs, which is smaller than Q antenna elements, may be considered as an intermediate form between digital BF and analog BF. In this case, although there are differences depending on the connection scheme of the B TXRU and the Q antenna elements, the beam directions that can be simultaneously transmitted are limited to B or less.

7 shows examples of a connection scheme of a TXRU and an antenna element.

7 (a) shows how a TXRU is connected to a sub-array. In this case the antenna element is connected to only one TXRU. 6 (b) shows how the TXRU is connected to all antenna elements. In this case the antenna element is connected to all TXRUs. In FIG. 6, W denotes a phase vector multiplied by an analog phase shifter. That is, the direction of analog beamforming is determined by W. Here, the mapping between the CSI-RS antenna port and the TXRUs may be 1-to-1 or 1-to-multi.

As more communication devices demand larger communication capacities, there is a need for improved wireless broadband communication compared to existing radio access technology (RAT). In addition, Massive MTC (Machine Type Communications), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system design considering services / UEs that are sensitive to reliability and latency has been discussed. The introduction of the next-generation RAT in consideration of this point is discussed, and in the present invention referred to as NewRAT for convenience.

In order to minimize data transmission latency in the TDD system, the fifth generation NewRAT considers a self-contained subframe structure as shown in FIG. 8. 8 is an example of a self-contained subframe structure.

In FIG. 8, the hatched region represents a downlink control region, and the black portion represents an uplink control region. An area without an indication may be used for downlink data transmission or may be used for uplink data transmission. The feature of such a structure is that downlink transmission and uplink transmission are sequentially performed in one subframe, thereby transmitting downlink data and receiving uplink ACK / NACK in the subframe. As a result, when a data transmission error occurs, the time taken to retransmit data is reduced, thereby minimizing the latency of the final data transfer.

In this self-contained subframe structure, a time gap is required for a base station and a UE to switch from a transmission mode to a reception mode or a process of switching from a reception mode to a transmission mode. To this end, some OFDM symbols (OFDM symbols; OS) at the time of switching from downlink to uplink in a self-contained subframe structure are set to a guard period (GP).

As an example of the self-contained subframe type configurable / configurable in a system operating based on NewRAT, at least the following four subframe types may be considered.

Downlink Control Section + Downlink Data Section + GP + Uplink Control Section

Downlink control section + downlink data section

Downlink Control Section + GP + Uplink Data Section + Uplink Control Section

Downlink control section + GP + uplink data section

Hereinafter, a method of generating a sync signal and a method of indicating a sync signal index according to an embodiment of the present invention will be described.

1. Parameter Set and Default Subcarrier Spacing

The parameter set for the SS block can be defined according to the following.

Subcarrier spacing (bandwidth)

15 kHz (up to 5 MHz), 30 kHz (up to 10 MHz), 120 kHz (up to 40 MHz), 240 kHz (up to 80 MHz)

In addition, considering that 24RB is allocated for PBCH transmission, a transmission bandwidth of 4.32 MHz for a 15 kHz subcarrier and 34.56 MHz for a 120 kHz subcarrier are required. And, in the frequency range up to 6 GHz, the minimum possible carrier bandwidth for NR is 5 MHz, and in the frequency range from 6 GHz to 52.6 GHz, the minimum possible carrier bandwidth for NR is set at 50 MHz.

Accordingly, as described above, in the frequency range below 6 GHz, the subcarrier spacing of 15 kHz may be determined as the default numerologies, and in the frequency range above 6 GHz, the subcarrier spacing of 120 kHz may be determined as the basic numerology. More precisely, the subcarrier spacing of 120 kHz from the 6 GHz to 52.6 GHz frequency range can be determined as the basic numerology. However, we need to approach carefully the detection performance of PSS / SSS based 15kHz subcarriers at 6Ghz.

In addition, one may consider the possibility of introducing a larger subcarrier spacing for NR-SS transmission, for example, a 30 kHz or 240 kHz subcarrier spacing.

2. Transmission Bandwidth and NR-SS Sequence RE Mapping

Referring to FIG. 9, similar to the method in which the PSS / SSS sequence is mapped to the RE in LTE, the NR-SS sequence may be mapped to the REs located in the center portion of the transmission bandwidth and located at the edge of the transmission bandwidth. Some REs may be reserved as Guard Subcarriers. For example, if 12RB is used for NR-SS transmission, 127RE is used for NR-SS sequence and 17RE is reserved. In this case, the 64 th element of the NR-SS sequence may be mapped to the central subcarrier of the NR-SS transmission bandwidth.

Meanwhile, in consideration of mapping the NR-SS sequence to the RE, it may be assumed that a transmission bandwidth of 2.16 MHz is used for the 15 kHz subcarrier for the NR-SS transmission. In addition, if the subcarrier spacing increases by an integer multiple, the NR-SS bandwidth also increases by the same integer multiple.

That is, the bandwidth for NR-SS may be defined as follows according to the subcarrier spacing.

When the subcarrier spacing is 15 kHz, the NR-SS bandwidth may be 2.16 MHz.

When the subcarrier spacing is 30 kHz, the NR-SS bandwidth may be 4.32 MHz.

If the subcarrier spacing is 120kHz, the NR-SS bandwidth may be 17.28MHz.

If the subcarrier spacing is 240kHz, the NR-SS bandwidth may be 34.56MHz.

3. NR-PSS Sequence Design

In the NR system, to distinguish 1000 cell IDs, the number of NR-PSS sequences is defined as three, and the number of hypotheses of NR-SSS corresponding to each NR-PSS is defined as 334.

Timing ambiguity, PAPR, and detection complexity must be considered for NR-PSS design. In order to solve the timing ambiguity, an NR-PSS sequence can be generated using the M-sequence of the frequency domain. However, when generating an NR-PSS sequence using the M-sequence, it may have a relatively high PAPR characteristic. Therefore, when designing NR-PSS, it is necessary to study the frequency domain M-sequence with low PAPR characteristics.

On the other hand, the modified ZC sequence may be considered as the NR-PSS sequence. In particular, when using the method of generating four ZC sequences by arranging them consecutively in the time domain, the timing ambiguity problem can be solved, a low PAPR characteristic can be reduced, and the detection complexity can be reduced. In particular, in the NR system, in order to detect the NR-PSS having a wider transmission bandwidth than the multi-sequence and LTE, the detection complexity must increase, so a problem of reducing the detection complexity is very important in the NR-PSS design. Do.

Based on the above, two NR-PSS sequences can be considered.

(1) Frequency M-sequence with low PAPR

Polynomial: g (x) = x ⁷ + x ⁶ + x ⁴ + x + 1 (initial poly shift register value: 1000000)

Cyclic Shift: 0, 31, 78

(2) four consecutive ZC sequences in the time domain

31-length ZC sequence (root index: {1,30}, {7,24}, {4,27})

Equation for Sequence Generation

[Equation 1]

FIG. 10 is a diagram for briefly explaining a method for generating an NR-PSS using four consecutive ZC sequences in the time domain. Referring to FIG. 10, if the N sub-symbols are S1, S2, ..., Sn, concatenation sequences of S1, S2, ..., Sn before IFFT, and total sequence length. After performing Fourth Transform (DFT) Spreading, after mapping a plurality of sequences corresponding to each of N sub-symbols along a subcarrier, IFFT is performed without an out of band emission problem. A time domain sequence of _IFFT length can be obtained.

4. NR-SSS Sequence Design

The NR-SSS sequence is generated in one long sequence, which is generated by combining two M-sequences with different polynomials to produce 334 hypotheses. For example, if the Cyclic Shift value for the first M-sequence is 112 and the Cyclic Shift value for the second M-sequence is 3, a total of 336 hypotheses may be obtained. In this case, the scrambling sequence for NR-PSS can also be obtained by applying the third M-sequence.

If a relatively short period of NR-SS burst set is set, such as 5ms / 10ms, the NR-SS burst set may be transmitted several times within two 10ms radio frames. have.

Thus, if different NR-SSS sequences for multiple NR-SS burst sets are introduced, i.e., each time a NR-SS burst set is transmitted, if a different NR-SSS sequence is used, the UE may have a basic period. Each of a plurality of NR-SS burst sets transmitted in the network can be distinguished.

For example, if the NR-SS burst set is transmitted four times within the basic period, the original set of the NR-SSS sequence is applied to the first NR-SS burst set, and is applied to the second, third, and fourth NR-SS burst sets. It can be considered that an NR-SSS sequence different from the original set is used. Also, if two different NR-SSS sequence sets are used, one NR-SSS sequence set is used for the first and third NR-SSS burst sets, and another NR for the second and fourth NR-SSS burst sets. -SSS sequence set can be used.

The NR-SSS sequence defined in the NR system defines two M-sequences of length 127, and generates a final sequence by multiplying the elements included in each M-sequence.

That is, the NR-SSS sequence may be a scrambling sequence, given by NR-PSS, and its length may be 127, and may be determined by Equation 2 below.

[Equation 2]

d (n) = s _{1, m} (n) s _{2, k} (n) c _z (n) for n = 0, .., 126 and z = 0,1

Here, z = 0 may be used for the NR-SSS transmitted in the first SS burst set of two 10 ms radio frames. In addition, z = 1 may be used for the NR-SSS transmitted in the second, third and fourth SS burst sets.

At this time, the s _{1, m} (n) and s _{2, k} (n) can be determined by the following equation (3).

[Equation 3]

s _{1, m} (n) = S ₁ ((n + m) mod127),

s _{2, k} (n) = S ₂ ((n + k) mod127)

Here, m = N _ID1 mod112, K = floor (N _ID1 / 112), k = CS ₂ (K), 0 = N _ID1 = 333, and CS ₂ ∈ {48, 67,122}.

Finally, S _r (i) = 1-2x (i), 0 = i = 126, r = 1,2 to obtain S ₁ and S ₂ , where x (i) The polynomial can be defined by the following equation (4).

[Equation 4]

x (j + 7) = (x (j + 3) + x (j)) mod2, r = 1

x (j + 7) = (x (j + 3) + x (j + 2) + x (j + 1) + x (j)) mod2, r = 2

Here, the initial condition for x (i) is

x (0) = x (1) = x (2) = x (3) = x (4) = x (5) = 0, x (6) = 1, and a value of 0 = j = 119 Can have

Here, two scrambling sequences of C ₀ (n) and C ₁ (n) may be used as the preamble and the mid-amble signal of the SSS. These two scrambling sequences depend on the PSS, and can be defined by applying two different Cyclic Shifts to the M-sequence C (n) as shown in Equation 5 below.

[Equation 5]

c _z (n) = C ((n + p) mod 127)

where, p = CS ₁ (N _ID2 + 3 · z), CS ₁ ∈ {23, 69, 103, 64, 124, 24}, N _ID2 ∈ {0,1,2}

Here, C (i) = 1-2x (i), and 0 = i = 126, where the polynomial for x (i) can be defined by Equation 6 below.

[Equation 6]

x (j + 7) = (x (j + 5) + x (j + 4) + x (j + 3) + x (j + 2) + x (j + 1) + x (j)) mod2

Here, the initial condition for x (i) is x (0) = x (1) = x (2) = x (3) = x (4) = x (5) = 0, x (6) = 1 And may have a value of 0 = j = 119.

Now, look at the performance measurement results according to the above-described embodiments. In this experiment to measure the performance of NR-PSS, three NR-PSS design methods were considered. 1) Frequency domain M-sequence (traditional PSS sequence) 2) M-sequence with low PAPR 3) Sequence of four ZC sequences concatenated in the time domain.

In addition, the measurement for NR-SSS was used the NR-SSS sequence proposed in the present invention.

5. Measurement result according to the above-described NR-PSS sequence design

PAPR and CM

PAPR and CM measurement results for the aforementioned three types of NR-PSS sequences are shown in Table 1 below.

According to the above results, the PAPR / CM of the NR-PSS based on the sequence of four ZC sequences in the time domain is lower than the PAPR / CM of the NR-PSS based on the M-sequence. On the other hand, when comparing the M-sequence with the low PAPR and the frequency-domain M-sequence, the PAPR / CM of the M-sequence with the low PAPR is lower than the PAPR / CM of the frequency-domain M-sequence. PAPR / CM, on the other hand, is an important factor in determining the price of a power amplifier. Therefore, a low PAPR / CM NR-PSS design should be considered.

In conclusion, from the PAPR / CM perspective, NR-PSS based on ZC sequence shows better performance measurement than NR-PSS based on M-sequence, and based on M-sequence with low PAPR. NR-PSS shows better performance measurement than NR-PSS of frequency domain M-sequence.

Misdetection Rate

11 shows the measurement evaluation for each of the NR-PSS false detection rates described above. 11, it can be seen that the performance of each NR-PSS design is at a similar level. 12, it can be seen that a sequence connecting four ZC sequences has the lowest detection complexity.

Specifically, referring to FIG. 12, a sequence connecting four ZC sequences and a frequency domain sequence show similar detection performance. At this time, there is an advantage that the detection complexity of the sequence connecting the four ZC sequences is lower. In addition, when it is assumed that the above-described NR-PSS sequences have similar detection complexity, a sequence of four ZC sequences provides better performance than the M-sequence.

In conclusion, assuming that the detection complexity is the same, NR-PSS design detection performance based on ZC sequence provides better performance than that of frequency domain M-sequence.

6. Measurement result according to the above-described NR-SSS sequence design

Now, the detection performance according to the number of NR-SSS sequences is compared. For performance measurement, the conventional SSS sequence is compared with the proposed NR-SSS according to the present invention.

Brief information on the NR-SSS sequence design is as follows.

1) A single set of NR-SSS (with 334 hypotheses per NR-PSS sequence)

2) two sets of NR-SSS (with 668 hypotheses per NR-PSS sequence)

Referring to FIG. 13, even though the hypothesis of the NR-SSS sequence doubles, no special performance degradation is observed. Thus, in order to detect the boundary of the SS burst set within the basic period, the introduction of an additional set of NR-SSS can be considered.

Meanwhile, the parameters used in the measurement experiment according to FIGS. 11 to 13 are shown in Table 2 below.

7. SS block configuration

When the payload size of the PBCH is up to 80 bits, a total of four OFDM symbols may be used for SS block transmission. On the other hand, it is necessary to discuss the time position of NR-PSS / NR-SSS / NR-PBCH in the SS block including NR-PSS, NR-SSS, NR-PBCH. In the initial access state, the NR-PBCH can be used as a reference signal for precise time / frequency tracking. In order to improve the estimation accuracy, it is efficient to place two OFDM symbols for the NR-PBCH as far as possible. Accordingly, the present invention proposes that the first and fourth OFDM symbols of the SS block are used for NR-PBCH transmission as shown in FIG. 14 (a). Accordingly, a second OFDM symbol may be allocated to the NR-PSS and a third OFDM symbol may be used for the NR-SSS.

On the other hand, when the NR-SS is transmitted for the purpose of cell measurement or cell discovery, it is not necessary to transmit both the NR-PBCH and SS block time index indications. In this case, the SS block is composed of two OFDM symbols, as shown in FIG. 14 (b), the first OFDM symbol is allocated to the NR-PSS, and the second OFDM symbol is allocated to the NR-SSS.

Referring to FIG. 15A, the NR-PBCH is allocated within 288 REs, which is composed of 24 RBs. On the other hand, since the length of the NR-PSS / NR-SSS sequence is 127, 12 RBs are required for NR-PSS / NR-SSS transmission. In other words, in the case of the SS block configuration, the SS block is allocated within 24 RBs. In addition, SS blocks are preferably allocated within 24 RBs for RB grid alignment between different neurology, such as 15, 30, 60 kHz. In addition, since NR assumes a minimum bandwidth of 5 MHz, in which 25 RBs can be defined in 15 MHz subcarrier intervals, 24 RBs are used for SS block transmission. In addition, the NR-PSS / SSS should be located in the middle of the SS block, which may mean that the NR-PSS / SSS is allocated within the 7th to 18th RBs.

On the other hand, when configuring the SS block as shown in Figure 15 (a), in the 120kHz and 240kHz subcarrier interval, a problem may occur in the AGC (Automatic Gain Control) operation of the terminal. That is, in case of 120 kHz and 240 kHz subcarrier spacing, due to AGC operation, detection of NR-PSS may not be performed properly. Accordingly, as shown in the following two embodiments, it is possible to consider changing the SS block configuration. .

Example 1 PBCH-PSS-PBCH-SSS

Example 2 PBCH-PSS-PBCH-SSS-PBCH

That is, by placing the PBCH symbol at the beginning of the SS block and using the PBCH symbol as a dummy symbol for the AGC operation, the AGC operation of the terminal can be performed more smoothly.

On the other hand, NR-PSS / NR-SSS / NR-PBCH may be allocated, as shown in FIG. That is, NR-PSS may be allocated to symbol 0 and NR-SSS may be allocated to symbol 2. In addition, the NR-PBCH may be allocated to symbols 1 to 3, and in this case, symbols 1 and 3 may be mapped exclusively to the NR-PBCH. In other words, only NR-PBCH may be mapped to symbol 1 and symbol 3, and NR-SSS and NR-PBCH may be mapped to symbol 2 together.

8. SS Burst Configuration

In the present invention, look at how to determine the OFDM symbol capable of SS block transmission in the slot. CP type is set semi-statically with UE-Specific signaling, NR-PSS / SSS can support normal CP. Through this, in the initial connection, the CP detection problem can be solved.

However, in NR systems, it may include an Extend CP at every 0.5ms boundary. That is, when the SS block is located in the slot or between slots, the middle of the SS block may be at a 0.5 ms boundary. In this case, within the SS block, CPs of other lengths among NR-PSS and / or NR-SSS may be applied. At this time, if the UE assumes that a normal CP is applied to the NR-PSS and / or NR-SSS, and performs NR-SS detection, the detection performance may be degraded. Therefore, in NR, the SS block must be designed so that it does not cross the 0.5 ms boundary.

16 shows an example of an SS burst configuration for the TDD case. In an NR system, the DL control channel may be located in the first OFDM symbol in the slot and / or mini slot, and the UL control channel may be located in the last transmitted UL symbol. Therefore, in order to avoid collision between the SS block located in the slot and the DL / UL control channel, the SS block may be located in the middle of the slot.

The maximum number of SS blocks in an SS burst set is determined according to the frequency range. In addition, the candidate value of the number of SS blocks is determined according to the frequency range. On the other hand, the present invention, based on the SS burst configuration example of FIG. 16 will propose a total time interval required for SS block transmission in the SS burst set.

As shown in Table 3, if the subcarrier spacing of 30 kHz and 240 kHz is introduced for NR-SS transmission, it can be expected that the SS block will be transmitted within a maximum of 2 ms. However, since the default subcarrier spacing for NR-SS transmissions is 15 kHz and 120 kHz, a wider minimum system bandwidth, for example, 10 MHz for 30 kHz subcarrier spacing, 80 MHz for 240 kHz subcarrier spacing, to introduce 30 kHz and 240 kHz subcarrier spacing. It should be discussed whether to introduce it. If NR determines that it only supports a minimum system bandwidth of 5 MHz below 6 GHz and 50 MHz at 6 GHz, then an SS burst set should be designed for 15 kHz and 120 kHz subcarrier spacing. In the case where the maximum number of SS blocks is 6 GHz or less and 8 and 6 GHz or more, assuming 64, the time required for SS block transmission is 4 ms, so the system overhead is quite large. In addition, since a short overall time interval for SS block transmission is desirable from the viewpoint of network energy saving and UE measurement, the candidate location of the allocation for SS block transmission may have an N ms time duration (e.g., N = 0.5, Should be defined in 1, 2).

9. Configure SS burst aggregation

For the SS burst set configuration, as shown in FIG. 17, two types may be considered according to the SS burst period. One is the local type of FIG. 17 (a), where all SS blocks are transmitted continuously within the SS burst set, while the other is the distributed type of FIG. 17 (b), where the SS burst is periodic within the SS burst set period. Is sent to.

In terms of efficiency for energy saving and inter-frequency measurement for IDLE UE, the local type SS burst case provides an advantage over the distributed type SS burst case. Therefore, it would be more desirable to support a local type of SS burst.

Meanwhile, if the SS burst set is configured as a local type as shown in FIG. 17A, the uplink signal cannot be transmitted during the symbol period to which the SS burst set is mapped. Particularly, as the subcarrier spacing on which the SS block is arranged increases, the symbol size decreases in inverse proportion thereto, so that more symbol intervals in which an uplink signal cannot be transmitted become larger. It is necessary to leave a symbol for uplink transmission between SS bursts at regular intervals.

Referring to Fig. 18, there is shown an SS burst set configuration when the subcarrier spacing for arranging the SS blocks is 120 kHz and 240 kHz. Referring to FIG. 18, when the subcarriers of 120 kHz and 240 kHz are included, SS bursts are configured by leaving a predetermined interval in units of four SS bursts. In other words, the symbol interval for uplink transmission of 0.125ms is empty in units of 0.5ms, and SS blocks are arranged.

However, in the frequency range of 6 GHz or more, a subcarrier spacing of 60 kHz may be used for data transmission. That is, as shown in FIG. 19, in NR, a subcarrier spacing of 60 kHz for data transmission and a subcarrier spacing of 120 kHz or 240 kHz for SS block transmission may be multiplexed.

Meanwhile, when the SS block of the 120 kHz subcarrier spacing and the data of the 60 kHz subcarrier spacing are multiplexed, the collision or overlapping between the SS block of the 120 kHz subcarrier spacing and the GP and the downlink control region of the 60 kHz subcarrier spacing is multiplexed. You can see it happen. Collision between the SS block and the DL / UL control region should preferably be avoided, and therefore modification of the SS burst and SS burst set configuration is required.

In the present invention, two embodiments are proposed as a modification direction of the SS burst configuration to solve this problem.

The first embodiment is to change the position of the SS burst format 1 and SS burst format 2, as shown in FIG. That is, by exchanging the SS burst format 1 and the format 2 in the box of FIG. 20, it is possible to prevent a collision between the SS block and the DL / UL control region. In other words, SS burst format 1 is located at the front of the slot at 60 kHz subcarrier spacing and SS burst format 2 is located at the back of the slot at 60 kHz subcarrier spacing.

In summary, the above-described embodiments can be expressed as follows.

1) 120 KHz subcarrier spacing

the first OFDM symbols of the candidate SS / PBCH blocks have indexes {4, 8, 16, 20, 32, 36, 44, 48} + 70 * n. For carrier frequencies larger than 6 GHz, n = 0, 2, 4, 6.

the first OFDM symbols of the candidate SS / PBCH blocks have indexes {2, 6, 18, 22, 30, 34, 46, 50} + 70 * n. For carrier frequencies larger than 6 GHz, n = 1, 3, 5, 7.

2) 240 KHz subcarrier spacing

the first OFDM symbols of the candidate SS / PBCH blocks have indexes {8, 12, 16, 20, 32, 36, 40, 44, 64, 68, 72, 76, 88, 92, 96, 100} + 140 * n. For carrier frequencies larger than 6 GHz, n = 0, 2

the first OFDM symbols of the candidate SS / PBCH blocks have indexes {4, 8, 12, 16, 36, 40, 44, 48, 60, 64, 68, 72, 92, 96, 100, 104} + 140 * n. For carrier frequencies larger than 6 GHz, n = 1, 3

The second embodiment is a method of changing the SS burst set configuration, as shown in FIG. That is, the SS burst set may be configured such that the start boundary of the SS burst set and the start boundary of the 60 kHz subcarrier spacing slot are aligned, that is, coincident with each other.

Specifically, the SS burst is constituted by SS blocks placed locally for 1 ms. Thus, for 1 ms, an SS burst of 120 kHz subcarrier spacing has 16 SS blocks, and an SS burst of 240 kHz subcarrier spacing has 32 SS blocks. When the SS burst is configured in this way, one slot is allocated as a gap based on a subcarrier spacing of 60 kHz between the SS bursts.

The second embodiment described above is summarized as follows.

1) 120 KHz subcarrier spacing

the first OFDM symbols of the candidate SS / PBCH blocks have indexes {4, 8, 16, 20} + 28 * n. For carrier frequencies larger than 6 GHz, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18.

2) 240 KHz subcarrier spacing

the first OFDM symbols of the candidate SS / PBCH blocks have indexes {8, 12, 16, 20, 32, 36, 40, 44} + 56 * n. For carrier frequencies larger than 6 GHz, n = 0, 1, 2, 3, 5, 6, 7, 8.

10.The indication of actually transmitted SS / PBCH block within 5ms duration

In an NR system, in order to perform an initial access procedure, a candidate position for SS block transmission within an SS burst aggregation period (eg, 5 ms) may be specified. In addition, the position of the actual transmitted SS block can be notified to the CONNECTED / IDLE mode UE. In this case, the network may have the flexibility to utilize resources depending on the network conditions, but the flexibility of setting the SS burst set may differ depending on the configuration method that informs the SS block actually used. For example, if individual location information (eg, bit blocks for SS blocks or SS bursts) of the actual transmitted SS blocks can be set in the UE, both localized and distributed types are dependent on network conditions. Can be operated. In addition, this individual location information can be included in other SIs that represent measurement-related information.

In addition, the network configuration can change the period of the SS burst set and provide information of the measurement timing / duration time for the UE. However, when the SS burst set periodicity is changed, it is necessary to determine a candidate position of SS block transmission. In the present invention, two embodiments are described below with respect to a method for determining SS block transmission.

(Example 1) The network may use the assumption of candidate positions for the basic period.

(Embodiment 2) The network may indicate the actual position to transmit the SS block within the measurement interval.

That is, in the NR system, the SS burst aggregation configuration can be designed according to the basic period. In addition, when the SS burst set period and measurement duration are indicated by the network, the SS burst set configuration can be assumed by the SS burst setting. For example, if there is no indication from the network, assuming that the UE assumes a 5ms period as the SS burst set period for measurement, SS burst set may be configured for the 5ms period. In addition, this SS burst aggregation configuration may be used in the case of a basic period (for example, 20 ms) and a network set period (for example, 5, 10, 20, 40, 80, 160 ms).

On the other hand, for more efficient resource utilization for SS burst set configuration, the network may indicate the actual location for transmitting the SS block within the measurement duration. For example, for a basic period, NR-SS and NR-PBCH should be transmitted within the SS burst aggregation period. On the other hand, in the case of a period longer than the basic period, only the NR-SS can be transmitted for measurement purposes. If the network can set the actual location for SS block transmission, unused resources allocated to the NR-PBCH can be allocated to the data / control channel. In addition, in the case of a period shorter than the basic period, the network may select some SS blocks among the SS blocks in the SS burst set and set an SS block actually used.

Meanwhile, depending on the network environment, the number of candidates for SS block transmission may be limited. For example, the number of candidates may be different according to the subcarrier spacing in which the SS block is arranged. In this case, the position of the SS block actually transmitted can be informed to the CONNECTED / IDLE mode UE. In this case, the actual transmitted SS / PBCH block indication indicating the position of the SS block actually transmitted can be used for resource utilization purposes, for example, rate matching for the serving cell, and for the neighboring cell associated with the resource. It can be used for measurement purposes.

With regard to the serving cell, if the UE can correctly recognize the SS block that has not been transmitted, the UE can recognize that it can receive other information, such as paging or data, through the candidate resources of the untransmitted SS block. . For this resource flexibility, the SS block actually transmitted in the serving cell needs to be correctly indicated.

That is, since a resource to which the SS block is transmitted cannot receive other information such as paging or data, in order to increase efficiency of resource utilization by receiving other data or other signals through the SS block where the SS block is not actually transmitted, Needs to be aware of the SS block candidates for which the SS block is not actually transmitted.

Therefore, in order to accurately indicate the SS block actually transmitted in the serving cell, 4, 8, or 64 bits of full bitmap information are required. In this case, the bit size included in the bitmap may be determined according to the number of SS blocks that can be transmitted at the maximum in each frequency range. For example, in order to indicate the SS block actually transmitted in a 5 ms interval, 8 bits are required in the frequency range of 3 GHz to 6 GHz, and 64 bits are required in the frequency range of 6 GHz or more.

Bits for the SS block actually transmitted in the serving cell may be defined in the RMSI or OSI, which RMSI / OSI includes configuration information for data or paging. Since the actually transmitted SS / PBCH block indication is associated with the configuration for the downlink resource, it may be concluded that the RMSI / OSI includes the SS block information actually transmitted.

Meanwhile, the actual transmitted SS / PBCH block indication of the neighbor cell may be required for the purpose of neighbor cell measurement. However, if there are many listed cells, the indicator of the full bitmap type may excessively increase the signal overhead. Thus, in order to reduce signaling overhead, various compressed forms of indicators may be considered. On the other hand, not only for the purpose of measuring the neighboring cell, but also to reduce the signaling overhead, the indicator for the SS block transmitted by the serving cell may also consider the indicator in the compressed form. In other words, the SS block indicator described below can be used for the actual transmitted SS block indication of neighbor cells and serving cells. In addition, as described above, the SS burst may mean a bundle of SS blocks included in one slot according to each subcarrier. Hereinafter, the SS burst may be a certain number regardless of slots. It may mean an SS block group grouping SS blocks.

Referring to FIG. 22, referring to one embodiment, assuming that the SS burst is composed of eight SS blocks, there may be a total of eight SS bursts in a band of 6 GHz or more in which 64 SS blocks may be located. .

Here, grouping the SS blocks into SS bursts is for compressing a 64-bit entire bitmap. Instead of 64-bit bitmap information, 8-bit information indicating the SS burst including the SS block actually transmitted may be used. If 8-bit bitmap information indicates SS burst # 0, SS burst # 0 may include one or more SS blocks that are actually transmitted.

Here, additional information for additionally instructing the UE of the number of SS blocks transmitted per SS burst may be considered. SS blocks may exist locally in each SS burst by the number of SS blocks indicated by the additional information.

Therefore, by combining the number of SS blocks actually transmitted per SS burst indicated by the additional information and a bitmap for indicating the SS burst including the actually transmitted SS blocks, the UE may estimate the SS blocks actually transmitted. Can be.

For example, it can be assumed that the instruction shown in Table 4 below.

That is, according to Table 4, it can be seen that SS bursts # 0, # 1, and # 7 include SS blocks through an 8-bit bitmap, and additional information indicates that four SS blocks are included in each SS burst. As a result, it can be estimated that the SS block is transmitted through four candidate positions before the SS bursts # 0, # 1, and # 7.

On the other hand, unlike the above-described example, by transmitting the additional information in the bitmap format, it is possible to have the flexibility of the location where the SS block is transmitted.

For example, there may be a method of indicating the information related to the SS burst transmission in a bitmap and indicating the SS block transmitted in the SS burst in other bits.

That is, the total 64 SS blocks are divided into 8 SS bursts (that is, SS block groups), respectively, and the UE is informed of which SS burst is used for 8-bit bitmap transmission. Defining the SS burst, as shown in FIG. 22, when multiplexing with a slot having a subcarrier spacing of 60 kHz, there is an advantage in that the boundary of a slot having a SS burst and a slot having a subcarrier of 60 kHz is aligned. Accordingly, if the bitmap is instructed to turn on / off the SS burst, the terminal may recognize whether the SS block is transmitted in slot units for all subcarrier intervals in the 6Ghz or higher frequency band.

Here, the difference from the above example is that the additional information is informed in a bitmap manner. In this case, since bitmap information must be transmitted for eight SS blocks included in each SS burst, eight bits are required, and the additional information is commonly applied to all SS bursts. For example, bitmap information for SS bursts indicates that SS burst # 0 and SS burst # 1 are used, and additional bitmap information for SS blocks indicates that the first and fifth SS blocks within the SS burst If it is indicated to be transmitted, the first and fifth SS blocks are transmitted in both SS burst # 0 and SS burst # 1, so that the total number of SS blocks actually transmitted is four.

Meanwhile, some neighboring cells may not be included in the cell list, and neighboring cells not included in the cell list use a default format for the SS block actually transmitted. By using this basic format, the UE can perform measurements for neighbor cells not included in the list. In this case, the above-described basic format may be predefined or set by a network.

On the other hand, when the information on the actual SS block transmitted in the serving cell and the information on the actual SS block transmitted in the neighboring cell is in conflict, the terminal prioritizes the SS block information transmitted in the serving cell, Information on the transmitted SS block can be obtained.

That is, when information on the SS blocks actually transmitted is received in the form of a full bitmap and a grouping, since the accuracy of the information in the form of a full bitmap is likely to be high, the information in the form of a full bitmap is given priority. It can be used for SS block reception.

11. Signals and channels for time index indication

SS block time index indication is carried by the NR-PBCH. If the temporal index indication is included in a part of the NR-PBCH such as NR-PBCH content, scrambling sequence, CRC, redundancy version, etc., the indication is safely delivered to the UE. However, if the time index indication is included in a part of the NR-PBCH, it introduces additional complexity of decoding adjacent cell NR-PBCH. On the other hand, decoding of the NR-PBCH for neighboring cells may be possible, but this is not a requirement for system design. In addition, further discussion is needed regarding which signals and channels are suitable for carrying SS block time index indications.

In the target cell, SS block time index information should be securely transmitted to the UE since the SS block time index information will be used as reference information of time resource allocation for initial access related channel / signal, such as system information delivery, PRACH preamble, and the like. On the other hand, for the purpose of neighbor cell measurement, the time index is used for RSRP measurement at the SS block level. In such a case, the SS block time index information may not need to be very accurate.

In the present invention, it is proposed that the NR-PBCH DMRS is used as a signal for carrying the SS block time index. It is also proposed to include a time index indication in part of the NR-PBCH. Through this, the SS block time index can be detected from the NR-PBCH DMRS, and the detected index can be confirmed by NR-PBCH decoding. In addition, the index can be obtained from the NR-PBCH DMRS for the neighbor cell for neighbor cell measurement.

The time index indication may be configured through the following two embodiments.

(Example 1) A single index method in which an index is assigned to each of all SS blocks in a set of SS bursts.

(Embodiment 2) A multiple index method in which an index is assigned by a combination of an SS burst index and an SS block index.

If a single index method, such as Embodiment 1, is supported, a large number of bits are needed to represent the number of all SS blocks in the SS burst set period. In this case, the DMRS sequence and the scrambling sequence for the NR-PBCH preferably indicate an SS block indication.

On the other hand, as in the second embodiment, when the multiple index method is applied, flexibility of design for index indication may be provided. For example, both SS burst index and SS block index may be included in a single channel. In addition, each index may be transmitted separately through different channels / signals. For example, the SS burst index may be included in the content or scrambling sequence of the NR-PBCH, and the SS block index may be delivered through the DMRS sequence of the NR-PBCH.

11.SS block time index

In the present invention, for the energy saving of the network and the UE, it is proposed that the SS burst set is configured within a shorter duration (eg 2 ms). In this case, all SS blocks may be located within the SS burst aggregation period regardless of the period (eg, 5, 10, 20, 40, 80, 160 ms). 23 provides an example SS block index in the case of a 15 kHz subcarrier spacing.

A SS block index will be described with reference to FIG. 23. If the maximum number of SS blocks is defined as L, the index of the SS block is 0 to L-1. In addition, the SS block index is derived from the OFDM symbol index and the slot index. In addition, the SS burst set may be composed of four SS blocks located in two adjacent slots. Therefore, the index of the SS block is 0 to 3 and the slot index is defined as 0 and 1. In addition, the SS block is composed of four OFDM symbols, and two OFDM symbols in the SS block are used for PBCH transmission. In this case, the indexes of the OFDM symbols for the PBCH transmission may be 0 and 2. As shown in FIG. 23 (a), the index of the SS block is derived from the index of the OFDM symbol and the slot. For example, the SS block transmitted in slot # 1 and OFDM symbol # 2 is mapped to index 3.

As shown in Fig. 23 (b), in the NR system, the network may set the period of the SS burst set. In addition, short periods can be set, such as 5 and 10 ms. If so, more SS block transmissions can be allocated. The index of the SS block can be identified within a set period of the SS burst set. As shown in (c) of FIG. 23, when the periodicity is 5 ms, four SS blocks may be transmitted within a set period, and a total of 16 SS blocks may be transmitted within a basic period. In this case, the index of the SS block may be repeated within the default period, and among the 16 SS blocks, four SS blocks may have the same index.

12.NR-PBCH Content

In the NR system, based on the response LS of the RAN2, the payload size of the MIB is expected to be expanded. The expected MIB payload size and NR-PBCH content in the NR system are as follows.

1) Payload: 64 bit (48 bit information, 16 bit CRC)

2) NR-PBCH Content:

At least part of SFN / H-SFN

-Setup information for common search space

-Center frequency information of NR carrier

After the UE detects the cell ID and the symbol timing information, part of the timing information such as SFN, SS block index, half frame timing, common control channel related information such as time / frequency position, bandwidth, and bandwidth portion such as SS block position (Bandwidth part) information and information for network access can be obtained from a PBCH including SS burst set information such as SS burst set period and actually transmitted SS block index.

Since only a limited time / frequency resource of 576 RE is occupied for the PBCH, the PBCH must contain the necessary information. In addition, if possible, an auxiliary signal such as PBCH DMRS may be used to further include the required information or additional information.

(1) SFN (System Frame Number)

In NR, a system frame number (SFN) can be defined to distinguish 10 ms intervals. In addition, similar to the LTE system, an index between 0 and 1023 may be introduced for SFN, and the index may be explicitly indicated by using a bit or indicated in an implicit manner.

In NR, the PBCH TTI is 80ms and the minimum SS burst period is 5ms. Therefore, up to 16 times PBCH may be transmitted in units of 80 ms, and a different scrambling sequence for each transmission may be applied to PBCH encoded bits. The UE can detect the 10 ms interval similar to the LTE PBCH decoding operation. In this case, eight states of the SFN are implicitly indicated by the PBCH scrambling sequence, and 7 bits for the SFN indication can be defined in the PBCH contents.

(2) timing information in a radio frame

The SS block index may be explicitly indicated by bits included in the PBCH DMRS sequence and / or PBCH content according to the carrier frequency range. For example, for the frequency band below 6 GHz, 3 bits of the SS block index are transmitted only in the PBCH DMRS sequence. In addition, for the frequency band of 6 GHz or more, the least significant 3 bits of the SS block index are represented by the PBCH DMRS sequence, and the most significant 3 bits of the SS block index are carried by the PBCH content. In addition, the boundary of the half frame may be carried by the PBCH DMRS sequence. That is, in the frequency range of 6 GHz to 52.6 GHz, up to 3 bits for the SS block index may be defined in the PBCH content.

(3) information to identify that there is no RMSI corresponding to the PBCH

In NR, the SS block can be used not only for providing information for network access but also for measuring motion. In particular, for wideband CC operation, multiple SS blocks can be transmitted for measurement.

However, it may not be necessary for the RMSI to be passed through all frequency positions where the SS block is transmitted. That is, for efficiency of resource utilization, the RMSI may be delivered through a specific frequency position. In this case, UEs performing the initial access procedure may not recognize whether the RMSI is provided at the detected frequency position. In order to solve this problem, it is necessary to define a bit field for identifying that there is no RMSI corresponding to the PBCH of the detected frequency domain. On the other hand, it should also be considered how to identify that there is no RMSI corresponding to the PBCH without the bit field.

To this end, an SS block without RMSI is transmitted at a frequency position not defined as a frequency raster. In this case, since the UEs performing the initial access procedure cannot detect the SS block, the aforementioned problem can be solved.

(4) SS burst set periodicity and actually transmitted SS block

For measurement purposes, information about the SS burst set periodicity and the SS block actually transmitted may be indicated. Therefore, such information is preferably included in system information for cell measurement and inter / intra cell measurement. In other words, it is not necessary to define the above-mentioned information in the PBCH content.

(5) payload size

In consideration of the decoding performance of the PBCH, a maximum payload size of 64 bits can be assumed as shown in [Table 5].

13. NR-PBCH scrambling

Let's take a look at the type and sequence initialization of the NR-PBCH scrambling sequence. Consider using a PN sequence in NR, but if you do not have serious problems using the 31-length gold sequence defined in the LTE system as the NR-PBCH sequence, then reuse the gold sequence with the NR-PBCH scrambling sequence. It may be desirable.

In addition, the scrambling sequence can be initialized at least by Cell-ID, and 3 bits of the SS block index indicated by PBCH-DMRS can be used for initialization of the scrambling sequence. In addition, if the half frame indication is indicated by PBCH-DMRS or another signal, the half frame indication may also be used as a seed value for initialization of the scrambling sequence.

14. Transmission method and antenna port

In an NR system, NR-PBCH transmission is performed on a single antenna port basis. In addition, in the case of single antenna port-based transmission, the following embodiments may be considered as a method for NR-PBCH transmission.

(Example 1) TD-PVS (time domain precoding vector switching) method

Embodiment 2 Cyclic Delay Diversity (CDD) Method

(Example 3) Frequency Domain Precoding Vector Switching (FD-PVS)

According to the transmission scheme, the NR-PBCH may obtain a transmission diversity gain and / or a channel estimation performance gain. On the other hand, TD-PVS and CDD can be considered for NR-PBCH transmission, while FD-PVS is undesirable because of the overall loss of performance due to channel estimation loss.

In addition, looking at the antenna port assumptions for NR-SS and NR-PBCH, in the initial connected state, the NR system provides NR-SS and NR-PBCH to provide network flexibility for NR-SS and NR-PBCH transmission. May be considered to transmit through different antenna ports. However, depending on the network configuration, the UE may assume that the antenna ports of the NR-SS and the NR-PBCH are the same or different.

15.NR-PBCH DM-RS Design

In an NR system, DMRS is introduced for phase reference of the NR-PBCH. In addition, there are NR-PSS / NR-SSS / NR-PBCH in all SS blocks, and OFDM symbols in which NR-PSS / NR-SSS / NR-PBCH is located are continuous in a single SS block. However, assuming that the transmission scheme is different between NR-SSS and NR-PBCH, it cannot be assumed that NR-SSS is used as a reference signal for NR-PBCH demodulation. Therefore, in the NR system, the NR-PBCH must be designed on the assumption that NR-SSS is not used as a reference signal for NR-PBCH demodulation.

For DMRS design, DMRS overhead, time / frequency position and scrambling sequence must be considered.

Overall PBCH decoding performance may be determined by channel estimation performance and NR-PBCH coding rate. Since the number of REs for DMRS transmission has a trade-off between channel estimation performance and the PBCH coding rate, it is necessary to find an appropriate number of REs for DMRS. For example, better performance can be provided when four REs are allocated per RB for DMRS. When two OFDM symbols are allocated for NR-PBCH transmission, 192 REs are used for DMRS and 384 REs are used for MIB transmission. In this case, assuming that the payload size is 64 bits, a 1/12 coding rate, which is the same coding rate as that of the LTE PBCH, can be obtained.

In addition, when a plurality of OFDM symbols are allocated for NR-PBCH transmission, it is a question of which OFDM symbols include DMRS. In order to prevent performance degradation due to residual frequency offset, all OFDM symbols where NR-PBCH is located are located. It is desirable to have DMRSs in place. Therefore, DMRS may be included in all OFDM symbols for NR-PBCH transmission.

On the other hand, for the OFDM symbol position where the NR-PBCH is transmitted, the PBCH DMRS is used as the time / frequency tracking RS, and the farther between two OFDM symbols including the DMRS is more advantageous for precise frequency tracking, so that the first OFDM symbol and the fourth OFDM symbol may be allocated for NR-PBCH transmission.

In addition, according to this, the frequency position of the DMRS may assume a mapping by interleaving in the frequency domain, which may be shifted according to the cell ID. The evenly distributed DMRS pattern has the advantage of using DFT-based channel estimation, which provides optimal performance in the case of 1-D channel estimation. In addition, wideband RB bundling may be used to increase channel estimation performance.

For the DMRS sequence, a pseudo random sequence defined by the type of the gold sequence can be used. The length of the DMRS sequence may be defined as the number of REs for the DMRS per SS block, and the DMRS sequence may also be generated by the Cell-ID and the slot number / OFDM symbol index within 20 ms, which is the default period of the SS burst set. have. In addition, the index of the SS block may be determined based on the index of the slot and OFDM symbol.

Meanwhile, the NR-PBCH DMRS should be scrambled by 1008 Cell IDs and a 3-bit SS block index. This is because, when comparing the detection performance according to the hypothesis number of the DMRS sequence, the 3-bit detection performance was found to be most suitable for the hypothesis number of the DMRS sequence. However, since the detection performance of 4 to 5 bits seems to have almost no performance loss, it is also possible to use a hypothesis number of 4 to 5 bits.

In other words, the DMRS sequence may be initialized by the cell ID, the SS block index in the SS burst set, and the half frame indication. A specific initialization expression is as shown in Equation 7 below.

[Equation 7]

는 SS 블록 그룹 내의 SS 블록 인덱스이고,

셀 ID이면, HF는 {0, 1}의 값을 가지는 half frame indication 인덱스이다.here,

Is the SS block index within the SS block group,

If it is a cell ID, HF is a half frame indication index having a value of {0, 1}.

The NR-PBCH DMRS sequence may be generated using a 31-length gold sequence similar to the LTE DMRS sequence, or may be generated based on a 7 or 8 length gold sequence.

On the other hand, since the detection performance when using a 31-length gold sequence and a 7 or 8-length gold sequence is similar, the present invention proposes to use a 31-length gold sequence, such as LTE DMRS, if 6GHz or more In the frequency range, gold sequences longer than 31 can be considered.

In addition, BPSK and QPSK can be considered as modulation types for DMRS sequence generation. Although the detection performance of BPSK and QPSK is similar, the correlation performance of QPSK is superior to BPSK, so QPSK is more suitable as a modulation type of DMRS sequence generation. Do.

15. NR-PBCH DMRS Pattern Design

Regarding the frequency location of the DMRS, two DMRS RE mapping methods may be considered. The fixed RE mapping method is to fix the RS mapping region in the frequency domain, and the variable RE mapping method is to shift the RS position according to the cell ID using the Vshift method. Such a variable RE mapping method has an advantage of obtaining additional performance gains by randomizing the interference, and thus, it is more preferable to use the variable RE mapping method.

는 [수학식 8]를 통해 결정될 수 있다.Specifically, the variable RE mapping includes complex modulation symbols included in a half frame.

May be determined through Equation 8.

[Equation 8]

를 통해 결정될 수도 있다.Here, k and l represent subcarriers and OFDM symbol indices located in the SS block. Meanwhile,

It may be determined through.

Also, to improve performance, RS power boosting can be considered. When RS power boosting and Vshift are used together, interference from interfering Total Radiated Powers (TRPs) can be reduced. Also, considering the detection performance gain of RS power boosting, the ratio of PDSCH EPRE to reference signal EPRE is preferably -1.25 dB.

16.NR-PBCH TTI boundary Indication

The NR-PBCH TTI is 80 ms and the default period of the SS burst set is 20 ms. This means that the NR-PBCH is transmitted four times within the NR-PBCH TTI. When the NR-PBCH is repeated within the NR-PBCH TTI, it is necessary to indicate the boundary of the TTI. For example, similar to the LTE PBCH, the NR-PBCH TTI boundary may be indicated by the scrambling sequence of the NR-PBCH.

In addition, referring to FIG. 24, the scrambling sequence of the NR-PBCH may be determined by Cell-ID and TTI boundary indication. Since the SS burst aggregation period may have a plurality of values, the number of indices for the TTI boundary indication may be changed according to the SS burst aggregation period. For example, four indexes are required for the default periodicity (ie, 20 ms) and 16 indexes are needed for the shorter period (ie, 5 ms).

Meanwhile, the NR system supports both single beam and multibeam transmission. When a plurality of SS blocks are transmitted within an SS burst set period, an SS block index for each of the plurality of SS blocks may be allocated. For randomization between SS blocks for inter-cell, the scrambling sequence must be determined by the index associated with the SS block. For example, if the index of the SS block is derived from the index of the slot and OFDM symbol, the scrambling sequence of the NR-PBCH may be determined by the index of the slot and OFDM symbol.

In addition, if the network sets a short period in the SS burst set, such as 5 and 10 ms, the SS burst set can be transmitted more during the same time. In this case, the UE may have ambiguity regarding the TTI boundary of NR-PBCHs transmitted within the default period. For the NR-PBCH TTI boundary indication for a period shorter than the default period, another scrambling sequence of the NR-PBCH for a period shorter than the default period may be considered. For example, if a period of 5 ms SS burst set is assumed, 16 scrambling sequences for NR-PBCH are applied. This has the advantage of being able to indicate the exact boundary of NR-PBCH transmission within the NR-PBCH TTI. On the other hand, blind detection complexity for NR-PBCH decoding increases. Therefore, in order to reduce the blind decoding complexity of the NR-PBCH, it may be considered to apply different NR-SSS sequences to distinguish between the NR-SSS having a default period and the NR-SSS further transmitted within the default period. .

17. Time index indication method

Referring to FIG. 25, the time information includes a system frame number (SFN), a half frame interval, and an SS block time index. Each time information may be represented by 10 bits for SFN, 1 bit for Half frame, and 6 bits for SS block time index. At this time, a part of 10 bits for SFN may be included in PBCH content. In addition, the NR-PBCH DMRS may include 3 bits among 6 bits for the SS block index.

Embodiments of the time index indication method represented in FIG. 25 may be as follows.

Example 1: S2 S1 (PBCH scrambling) + S0 C0 (PBCH contents)

Example 2: S2 S1 S0 (PBCH scrambling) + C0 (PBCH contents)

Example 3: S2 S1 (PBCH scrambling) + S0 C0 (PBCH DMRS)

Example 4: S2 S1 S0 (PBCH scrambling) + C0 (PBCH DMRS)

If a half frame indication is delivered through NR-PBCH DMRS, additional performance improvement may be brought about by combining PBCH data every 5ms. For this reason, as in Embodiments 3 and 4, one bit for half frame indication may be transmitted through the NR-PBCH DMRS.

Comparing Embodiments 3 and 4, Embodiment 3 can reduce the number of blind decoding times, but may result in loss of PBCH DMRS performance. If the PBCH DMRS can deliver 5 bits including S0, C0, B0, B1, B2 with excellent performance, the third embodiment will be suitable as a time indication method. However, if the above 5 bits cannot be delivered with excellent performance by the PBCH DMRS, the fourth embodiment will be suitable as a time indicating method.

In view of the foregoing, the highest 7 bits of the SFN may be included in the PBCH content, and the lowest 2 bits or 3 bits may be transmitted through PBCH scrambling. In addition, the least significant 3 bits of the SS block index may be included in the PBCH DMRS, and the most significant 3 bits of the SS block index may be included in the PBCH content.

In addition, we can consider how to obtain the SS block time index of the neighboring cell. Since decoding through the DMRS sequence performs better than decoding through the PBCH content, by changing the DMRS sequence within each 5ms period. 3 bits of the SS block index can be transmitted.

Meanwhile, in the frequency range below 6 GHz, the SS block time index may be transmitted using only the NR-PBCH DMRS of the neighbor cell. In the frequency range above 6 GHz, 64 SS block indexes may be divided by PBCH-DMRS and PBCH contents. As indicated, the UE needs to decode the PBCH of the neighbor cell.

However, decoding PBCH-DMRS and PBCH content together can result in additional complexity of NR-PBCH decoding and can reduce the decoding performance of PBCH than using only PBCH-DMRS. Therefore, it may be difficult to decode the PBCH to receive the SS block of the neighbor cell.

Therefore, instead of decoding the PBCH of the neighbor cell, it may be considered that the serving cell provides a setting related to the SS block index of the neighbor cell. For example, the serving cell provides configuration regarding the most significant 3 bits of the SS block index of the target neighbor cell, and the UE detects the least significant 3 bits through the PBCH-DMRS. In addition, the SS block index of the target neighbor cell may be obtained by combining the highest 3 bits and the lowest 3 bits.

18. Soft Combining

The NR system must support wise soft combining, at least for the SS burst set, for efficient resource utilization and PBCH coverage. Since the NR-PBCH is updated every 80 ms and the SS burst set is transmitted at a default period of 20 ms, at least four times soft combining is possible for NR-PBCH decoding. Also, when an SS burst set is indicated with a period shorter than the default period, more OFDM symbols may be used for soft combining for the PBCH.

19.PBCH decoding for the neighboring cell measurements

For neighbor cell measurement, it is a question whether the UE should decode NR-PBCHs of neighbor cells, since decoding of neighbor cells increases UE complexity, so it is better not to increase unnecessary complexity. Thus, for the NR-PBCH design, the UE should assume that it is not necessary to decode the neighbor cell NR-PBCH for neighbor cell measurement.

On the other hand, if the SS block index is delivered by a specific type of signal, the UE may perform signal detection to obtain the SS block index of neighboring cells, which may reduce the complexity of the US. On the other hand, the specific type of signal, NR-PBCH DMRS may be used.

20. Evaluate the measurement results

Now, the performance measurement results according to payload size, transmission scheme, and DMRS will be described. In this case, it is assumed that two OFDM symbols having 24 RBs are used for NR-PBCH transmission. In addition, the SS burst set (ie, 10, 20, 40, 80 ms) may have a plurality of periods, and it is assumed that the encoded bits are transmitted within 80 ms.

(1) Payload Size and NR-PBCH Resources

26 provides evaluation results according to MIB payload size (eg, 64, 80 bits). Here, assume that 384 REs and 192 REs for DMRS are used within two OFDM symbols and 24 RBs. It is also assumed that a single antenna port based transmission scheme, i.e., TD-PVS, is used.

Referring to FIG. 26, the NR-PBCH having a 20 ms period shows an error rate of 1% at -6 dB SNR. In addition, it can be seen that the 64-bit payload has a gain of 0.8 dB compared with the 80-bit payload case. Thus, if a payload size between 64 and 80 bits is assumed, the performance requirement of NRR-PBCH (ie, 1% BLER at -6dB SNR) can be met using 24RB and two OFDM symbols.

(2) transmission method

FIG. 27 provides evaluation results according to the NR-PBCH transmission scheme, such as TD-PVS and FD-PVS. The precoder is cycled in every PBCH transmission subframe for the TD-PVS (eg, 20 ms) and in all N RBs (eg, N is 6) for the FD-PVS. In addition, in FIG. 27, soft coupling of NR-PBCH is assumed, over several periods of SS burst set (ie, 10, 20, 40, 80 ms) and SS burst set within 80 ms.

As shown in FIG. 27, the time-domain precoding vector switching (TD-PVS) scheme has excellent channel estimation performance, and shows better performance than frequency domain precoding vector switching (FD-PVS). Here, it can be seen that channel estimation performance is more important than transmit diversity gain in a very low SNR region.

(3) DMRS Density

In the low SNR region, channel estimation performance improvement is an important factor for demodulation performance improvement. However, if the RS density of the NR-PBCH is increased, the channel estimation performance is improved, but the coding speed is decreased. Therefore, to compromise between channel estimation performance and channel coding gain, the decoding performance is compared according to the DMRS density. 28 is an illustration for DMRS density.

28 (a) uses 2RE per symbol for DMRS, FIG. 28 (b) uses 4RE per symbol, and FIG. 28 (c) uses 6RE per symbol for DMRS. In addition, this evaluation assumes that a single port based transmission scheme (ie, TD-PVS) is used.

28 is an embodiment of a DMRS pattern for single antenna port based transmission. Referring to FIG. 28, the DMRS position in the frequency domain maintains the same distance between the reference signals, but the RS density is changed. In addition, FIG. 29 shows a performance result according to the reference signal density of the DMRS.

As shown in FIG. 29, the NR-PBCH decoding performance of FIG. 28 (b) is superior to that of FIG. 28 (a) because channel estimation performance is excellent. On the other hand, Fig. 28 (c) is not as good as Fig. 28 (b) because the effect of coding rate loss is greater than the gain of channel estimation performance improvement. For the reasons mentioned above, designing with an RS density of 4 RE per symbol seems to be most appropriate.

(4) DMRS time position and CFO estimation

If the NR system supports self-contained DMRS, fine frequency offset tracking can be performed using self-contained DMRS for the NR-PBCH. Since the frequency offset estimation accuracy depends on the OFDM symbol distance, three types of NR-PBCH symbol intervals can be assumed as shown in FIG.

According to each NR-PBCH symbol interval shown in FIG. 30, CFO estimation is performed at an SNR of -6 dB, and a sample of 10% CFO (1.5 kHz) was applied in the subframe. In addition, four REs per symbol are used as independent RSs and included in symbols in which a PBCH is transmitted.

31 and 32 show CDFs of estimated CFOs according to different NR-PBCH symbol intervals. As can be seen in Figures 31 and 32, the CFO of 1.5 kHz is well estimated in both cases up to 90% of the UE within ± 200 Hz error range, with 95% of UEs when introducing at least 2 symbols in the NR-PBCH symbol interval. Is ± 200 Hz and 90% of UEs show errors within ± 100 Hz in both cases.

The phase offset due to the CFO increases as the interval increases, and the CFO estimation performance is better when the interval between PBCH symbols is larger, making it easier to measure the phase offset, like noise suppression. In addition, a large average window can increase the accuracy of the CFO estimation.

Now, the detection performance of the SS block index according to the number of DMRS sequence hypotheses, modulation type, sequence generation, and DMRS RE mapping will be described. In this measurement result, it is assumed that two OFDM symbols in 24RBs are used for NR-PBCH transmission. In addition, multiple periods of the SS burst set may be considered, which period may be 10 ms, 20 ms or 40 ms.

(5) the number of DMRS sequence hypotheses

33 shows measurement results based on the SS block index. Here, 144REs are used for DMRS and 432REs for information within 24RB and two OFDM symbols. And, the DMRS sequence assumes that a long sequence (eg, a gold sequence of length 31) and QPSK are used.

33 shows an error rate of 1% at -6dB when measuring two to three bits of detection performance. Therefore, 3 to 5 bits of information can be used as a hypothesis number for the DMRS sequence in terms of detection performance.

(6) modulation type

34 to 35 show the results of performance measurement comparing BPSK and QPSK. In this experiment, the DMRS hypothesis is 3 bits, the DMRS sequence is based on a long sequence, and the power level of the interference TRP is the same as the power level of the serving TRP.

34 to 35, it can be seen that the performance of the BPSK and QPSK is similar. Therefore, no matter what modulation type is used as the modulation type for the DMRS sequence, there is no difference in terms of performance measurement. However, referring to FIG. 36, it can be seen that each correlation characteristic when BPSK and QPSK is used is different.

Referring to FIG. 36, BPSK is distributed more in a region having a correlation amplitude of 0.1 or more than QPSK. Therefore, when considering a multi-cell environment, it is preferable to use QPSK as a modulation type of DMRS. That is, in terms of correlation characteristics, QPSK is a more suitable modulation type for a DMRS sequence.

(7) Sequence generation of PBCH DMRS

37 to 38 show measurement results according to DMRS sequence generation. The DMRS sequence may be generated based on a long sequence of polynomial order 30 or more or a short sequence of polynomial order 8 or less. In addition, it is assumed that the hypothesis for DMRS is 3 bits, and the power level of the interfering TRP is the same as the serving TRP.

37 to 38, it can be seen that the detection performance of the short sequence based generation is similar to the detection performance of the long sequence based generation.

(8) DMRS RE Mapping

39 shows the results of performance measurement according to the RE mapping method. Here, the hypothesis for DMRS is 3 bits, the DMRS sequence is based on a long sequence, and the interference TRP power level is the same as the serving TRP. In addition, only one source of interference exists.

As can be seen in Figure 39, by using a variable RE mapping, it is possible to obtain the effect that the interference is randomly distributed. Therefore, the detection performance of the variable RE mapping is superior to the fixed RE mapping performance.

40 shows measurement results when RS power boost is used. Here, it is assumed that RE transmission power for DMRS is 1.76 dB higher than RE transmission power for PBCH data. Combining variable RE mapping with DMRS power boosting reduces the interference of other cells. As can be seen in Figure 40, the performance with RS power boosting has a gain of 2-3 dB over no RS power boost.

In contrast, RS power boosting reduces the RE transmit power for PBCH data. Thus, RS power boosting can affect PBCH performance. 41 to 42 show the results of measuring PBCH performances with and without RS power boosting. Here, it is assumed that the period of the SS burst set is 40ms, and the encoded bits are transmitted within 80ms.

If the transmit power of the RE for PBCH data is reduced, performance loss may occur. However, demodulation performance can be improved because channel estimation performance is improved due to an increase in RS power. Thus, as can be seen from Figs. 41 to 42, the performance in both cases is almost the same. Therefore, the effect of the transmit power loss of the RE on the PBCH data can be compensated by the gain of the channel estimation performance.

Table 6 below shows the assumptions of the parameters used for the above-described performance measurement.

21. Bandwidth part (BWP) for downlink common channel transmission

The initial access procedure of LTE operates within the system bandwidth configured by the MIB. In addition, PSS / SSS / PBCH is arranged based on the center of the system bandwidth. The common search space is defined within the system bandwidth, system information is carried by the PDSCH allocated within the system bandwidth, and the RACH procedure for Msg1 / 2/3/4 operates within the system bandwidth.

On the other hand, while the NR system supports the operation within the wideband CC, it is very difficult in terms of cost to implement the UE has the capability to perform the required operation in all the wideband CC. Therefore, it may be difficult to implement the initial access procedure to operate smoothly within the system bandwidth.

In order to solve this problem, as shown in FIG. 42, the NR may define a BWP for an initial access operation. In the NR system, an initial access procedure for SS block transmission, system information delivery, paging, and RACH procedure may be performed in a BWP corresponding to each UE. In addition, the at least one downlink BWP may include one CORESET having a common search space in at least one primary component carrier.

Accordingly, downlink control information related to at least RMSI, OSI, Paging, and RACH message 2/4 may be transmitted in a CORESET having a common search space, and a downlink data channel associated with the downlink control information may be allocated in a downlink BWP. . In addition, the UE may expect the SS block to be transmitted in the BWP corresponding to the UE.

That is, in NR, at least one downlink BWPs may be used for downlink common channel transmission. Here, the signals that may be included in the downlink common channel may include an SS block, a CORSET having a common search space, and a PDSCH for RMSI, OSI, paging, RACH message 2/4, and the like.

(1) Neumerology

In NR, subcarrier spacings of 15, 30, 60 and 120 kHz are used for data transmission. Therefore, the neurology for the PDCCH and PDSCH in the BWP for the downlink common channel may be selected from among the numerologies defined for data transmission. For example, one or more of 15 kHz, 30 kHz, and 60 kHz subcarrier spacing may be selected for a frequency range below 6 GHz, and one or more of 60 kHz and 120 kHz subcarrier spacing may be selected for a frequency range of 6 GHz to 52.6 GHz. .

However, in the frequency range below 6 GHz, the subcarrier spacing of 60 kHz is already defined for the URLLC service, so the 60 kHz subcarrier spacing is not suitable for PBCH transmission in the frequency range below 6 GHz. Therefore, subcarrier spacing of 15 kHz and 30 kHz may be used for downlink common channel transmission in a frequency range of 6 GHz or less, and subcarrier spacing of 60 kHz and 120 kHz may be used in a frequency range of 6 GHz or more.

On the other hand, NR supports subcarrier spacing of 15, 30, 120, and 240 kHz for SS block transmission. It can be assumed that the same subcarrier spacing is applied to downlink channels such as CORESET and RMSI, paging, and RAR having a common search space with the SS block. Therefore, applying this assumption, it is not necessary to define the neuralology information in the PBCH content.

Conversely, the subcarrier spacing for the downlink control channel can be changed. For example, if a 240 kHz subcarrier spacing is applied to SS block transmission in a frequency band of 6 GHz or more, a change of the subcarrier spacing is necessary for data transmission because the 240 kHz subcarrier spacing is not defined for data transmission. Therefore, the SCS can be changed for data transmission and can be indicated through the 1-bit indicator in the PBCH content. Depending on the carrier frequency range, the upper one bit indicator may be interpreted as {15, 30 kHz} or {60, 120 kHz}. In addition, the indicated subcarrier spacing may be regarded as the reference neurology of the RB grid.

(2) BWP Bandwidth for Downlink Common Channel Transmission

In an NR system, the bandwidth of the BWP for the downlink common channel need not be the same as the system bandwidth over which the network operates. That is, the bandwidth of the BWP may be narrower than the system bandwidth. That is, the bandwidth should be wider than the carrier minimum bandwidth, but not wider than the UE minimum bandwidth.

Accordingly, the BWP for downlink common channel transmission may be defined such that the bandwidth of the BWP is wider than the bandwidth of the SS block and is equal to or smaller than a specific downlink bandwidth of all UEs capable of operating in each frequency range. For example, in the frequency range below 6GHz, the carrier minimum bandwidth is defined as 5MHz and UE minimum bandwidth can be assumed to be 20MHz. In this case, the bandwidth of the downlink common channel may be defined in the range of 5MHz ~ 20MHz.

(3) bandwidth setting

44 shows an example of bandwidth setting.

The UE attempts to detect a signal within the bandwidth of the SS block during an initial synchronization procedure that includes cell ID detection and PBCH decoding. Thereafter, the UE may continue to perform the next initial access procedure within the bandwidth for the downlink common channel. That is, the UE may acquire system information and perform RACH procedure.

Meanwhile, an indicator for the relative frequency position between the bandwidth for the SS block and the bandwidth for the downlink common channel may be defined in the PBCH content. In order to simplify the indication of the relative frequency position, the bandwidth for the plurality of SS blocks may be a candidate position for positioning the SS block within the bandwidth for the downlink common channel.

For example, assuming that the bandwidth of the SS block is 5 MHz and the bandwidth of the downlink common channel is 20 MHz, four candidate positions for finding the SS block within the bandwidth for the downlink common channel may be defined.

22. CORESET setting

(1) CORESET information and RMSI scheduling information

Rather than directly indicating scheduling information for the RMSI, it may be more efficient for the network to send the CORESET information including the RMSI scheduling information to the UE. That is, in the PBCH content, frequency resource related information, such as bandwidth for CORESET and frequency location, may be indicated. In addition, time resource related information, such as starting OFDM symbol, duration and number of OFDM symbols, may be additionally set to flexibly use network resources.

In addition, information about common search space monitoring period, duration and offset may also be transmitted from the network to the UE to reduce the UE detection complexity.

Meanwhile, the transmission type and the REG bundling size may be fixed according to the CORESET of the common search space. Here, the transmission type may be classified according to whether the transmitted signal is interleaved.

(2) the number of OFDM symbols included in the slot

Regarding the number of OFDM symbols in a slot or a carrier frequency range of 6 GHz or less, two candidates are considered, 7 OFDM symbol slots and 14 OFDM symbol slots. If the NR system decides to support both types of slots for the carrier frequency range of 6 GHz or less, it should be possible to define the indication method for the slot type to indicate the time resource of the CORESET with a common search space. .

(3) bit size of PBCH content

About 14 bits can be designated as shown in Table 7 to display the numeology, bandwidth, and CORESET information in the PBCH content.

Referring to FIG. 45, the communication device 4500 includes a processor 4510, a memory 4520, an RF module 4530, a display module 4540, and a user interface module 4550.

The communication device 4500 is shown for convenience of description and some modules may be omitted. In addition, the communication device 4500 may further include necessary modules. In addition, some modules in the communication device 4500 may be classified into more granular modules. The processor 4510 is configured to perform an operation according to the embodiment of the present invention illustrated with reference to the drawings. In detail, the detailed operation of the processor 4510 may refer to the contents described with reference to FIGS. 1 to 44.

The memory 4520 is connected to the processor 4510 and stores an operating system, an application, a program code, data, and the like. The RF module 4530 is connected to the processor 4510 and performs a function of converting a baseband signal into a radio signal or converting a radio signal into a baseband signal. For this purpose, the RF module 4530 performs analog conversion, amplification, filtering and frequency up conversion, or a reverse process thereof. The display module 4540 is connected to the processor 4510 and displays various information. The display module 4540 may use well-known elements such as, but not limited to, a liquid crystal display (LCD), a light emitting diode (LED), and an organic light emitting diode (OLED). The user interface module 4550 is connected to the processor 4510 and may be configured with a combination of well-known user interfaces such as a keypad and a touch screen.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

Certain operations described in this document as being performed by a base station may in some cases be performed by an upper node thereof. That is, it is obvious that various operations performed for communication with the terminal in a network including a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

The above-described method for receiving a synchronization signal and an apparatus therefor have been described with reference to the example applied to the fifth generation NewRAT system, but may be applied to various wireless communication systems in addition to the fifth generation NewRAT system.

Claims (19)

In a wireless communication system, a method for receiving a downlink signal by a terminal operating in a frequency band of 6GHz or more,
A system comprising first information associated with one or more SS / PBCH block groups and second information associated with one or more SS / PBCH blocks for each of the one or more SS / PBCH block groups. Receive information,
Receive the downlink signal from resources other than resources used for SS / PBCH blocks included in each of the one or more SS / PBCH block groups notified by the first information and the second information,
The first information is for informing the one or more SS / PBCH block group to which each of the one or more SS / PBCH blocks are transmitted,
The second information is for informing the one or more SS / PBCH blocks transmitted in each of the one or more SS / PBCH block groups,
The second information is used for the one or more SS / PBCH block groups known by the first information,
The one or more SS / PBCH blocks transmitted include a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a PBCH.
Downlink signal receiving method. The method of claim 1,
The first information is in the form of a bitmap,
The length of the bitmap is 8 bits,
Downlink signal receiving method. The method of claim 2,
A value of 1 in the bitmap indicates that the SS / PBCH block is transmitted in the corresponding SS / PBCH block group.
Downlink signal receiving method. The method of claim 1,
Wherein the second information is in the form of a bitmap,
Downlink signal receiving method. The method of claim 4, wherein
A value of 0 in the bitmap indicates that the corresponding SS / PBCH block is not transmitted, and a value of 1 indicates that the corresponding SS / PBCH block is transmitted.
Downlink signal receiving method. The method of claim 1,
The second information is,
Including information about the number of one or more SS / PBCH blocks transmitted;
Downlink signal receiving method. The method of claim 1,
The system information is received in a system information block (SIB),
Downlink signal receiving method. The method of claim 1,
The terminal assumes that reception Occasions for the PBCH, the PSS, and the SSS are in the form of SS / PBCH blocks on consecutive symbols.
Downlink signal receiving method. In a wireless communication system, a terminal operating in a frequency band of 6GHz or more for receiving a downlink signal,
Transceiver; And
A processor coupled to the transceiver;
The processor,
A system comprising first information associated with one or more SS / PBCH block groups and second information associated with one or more SS / PBCH blocks for each of the one or more SS / PBCH block groups. Control the transceiver to receive information,
The transceiver is configured to receive the downlink signal on resources other than resources used for SS / PBCH blocks included in each of the one or more SS / PBCH block groups notified by the first information and the second information. Control,
The first information is for informing the one or more SS / PBCH block group to which each of the one or more SS / PBCH blocks are transmitted,
The second information is for informing the one or more SS / PBCH blocks transmitted in each of the one or more SS / PBCH block groups,
The second information is used for the one or more SS / PBCH block groups known by the first information,
The one or more SS / PBCH blocks transmitted include a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a PBCH.
Terminal. The method of claim 9,
The first information is in the form of a bitmap,
The length of the bitmap is 8 bits,
Terminal. The method of claim 10,
A value of 1 in the bitmap indicates that the SS / PBCH block is transmitted in the corresponding SS / PBCH block group.
Terminal. The method of claim 9,
Wherein the second information is in the form of a bitmap,
Terminal. The method of claim 12,
A value of 0 in the bitmap indicates that the corresponding SS / PBCH block is not transmitted, and a value of 1 indicates that the corresponding SS / PBCH block is transmitted.
Terminal. The method of claim 9,
The second information is,
Including information about the number of one or more SS / PBCH blocks transmitted;
Terminal. The method of claim 9,
The system information is received in a system information block (SIB),
Terminal. The method of claim 9,
The terminal assumes that reception Occasions for the PBCH, the PSS, and the SSS are in the form of SS / PBCH blocks on consecutive symbols.
Terminal. delete delete delete

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